The miRNA expression profiles in EC cells differentiating in response to RA. (a) Sets of miRNAs expressed in P19 and NT2/D1 cells treated with RA. All RA-induced miRNAs in P19 and NT2/D1 cells are also expressed in the brain (Figures 1, 2). Numbers in overlapping areas indicate the amount of miRNAs that belong to intersecting sets. (b) Clustering of the 19 miRNAs induced by RA-treatment in both P19 and NT2/D1 cells by their similar expression profile in mouse (Mm) and human (Hs) brain (B), liver (Li), heart (H), muscle (M), lung (Lu), kidney (K) and spleen (S). Colored bars to the right of miRNA names indicate miRNA expression classes in reference to the pie chart on the left: brain-specific (red), brain-enriched (purple), or brain-nonenriched (grey). (c) Northern blots of representative RA-induced miRNAs, constitutively expressed miRNAs (miR-92), and nonexpressed miRNAs (miR-1d) in P19 and NT2/D1 cells treated with RA.